1. Field of the Invention
The invention relates to the technical field of electrochemistry and describes a compound membrane for electrochemical devices. Furthermore, a process for producing the compound membrane and its use are described.
2. Background
In some general aspects, an electrochemical device includes an electrochemical compressor through which a working fluid that includes a component that primarily acts as an electrochemically-active component flows; a sealed vessel in which the electrochemical compressor is housed; an inlet conduit for passing working fluid into the vessel; and an outlet conduit for passing fluid out of the vessel. The working fluid that leaks from the electrochemical compressor is contained within the vessel. An electrochemical compressor is disclosed in U.S. patent application Ser. No. 12/626,416 entitled “Electrochemical Compressor and Refrigeration System,” filed on Nov. 25, 2009, which is hereby incorporated by reference in its entirety.
Implementations can include one or more of the following features. For example, the electrochemical compressor can include one or more electrochemical cells. Each electrochemical cell includes an anode, a cathode, and an electrolytic membrane between and in intimate electrical contact with the cathode and the anode to pass the working fluid. The membrane is used as the electrolyte and at the same time as the separator to separate the anode from the cathode.
The electrolytic membrane preferably comprises proton-conducting polymer materials. These materials will hereinafter also be referred to as ionomers for short. Some existing products include Nafion® by DuPont. Other suitable ion-conducting membranes are described by O. Savadogo in “Journal of New Materials for Electrochemical Systems” I, 47-66 (1998).
The energy efficiency of the electrochemical devices depends on the various factors such as available surface area of the anode and the cathode, the thickness of the membranes, the current density and operating voltage applied to the cells from the power supply. Further, the life of the membrane depends on the chemical properties of the membranes. Any improvement in efficiency related to compressor performance can have significant benefits in terms of energy savings and thus have significant positive environmental impact. It was therefore an object of the present invention to provide a membrane which overcomes the disadvantages of the prior art and, in particular, has an improved construction concept.